Electronic tube circuits



F ch. 6, 1940.

H. P. DONLE 2,189,461 ELECTRONIC TUBE CIRCUITS Filed June 15, 1937 2 Sheets-Sheet l INVENTOR. Hamid P 0077/6 BY wv/a ATTORNEY.

Feb 6 940. H. P. DONLE 2,189,451

ELECTRONIC TUBE CIRCUITS Filed June 15, 19s"! 2 Sheets-Sheet 2 INVENT OR.

f/ara/d P 0077K? m ATTORNEY.

Patented Feb. 6, 1940 UNITED STATES PATENT OFFlCE ELECTRONIC TUBE CIRCUITS Harold P. Donle, New York, N. Y., assignor, by mesne assignments, to American Radiator & Standard Sanitary Corporation, New York, N. Y., a corporation of Delaware Application June 15, 1937, Serial No. 148,335

6 Claims.

My invention relates to improvements in means for operating or controlling electromechanical devices or other instruments in response to weak, infinitesimal or minute energy impulses or variations, and the same has for its object toprovide a simple, reliable and efficient system for controlling an electronic tube or valve in response to said impulses or variations for causing the desired variation in the output or working current of the tube for operation of my said invention; 10, the device or instrument. Fig. 2 is a circuit diagram of the system includ- Further, said invention has'for its object to ing one form of translating means responsive-to provide a method and system for carrying out the activating energy impulses for converting said method, whereby to render said minute or the same into the corresponding potential varia- Weak energy impulses or variations available for tion for operating the system, said translating 15, activating the control tube or valve of the sysmeans being shown asa bridge circuit in operatem with maximum eiliciency or sensitivity withtive relation with the input end of the system; out requiring the prior amplification of the Fig. 3 is a, circuit diagram of the output porelectrical impulses resulting from or correspondtion of my system showing a glow discharge tube ing to said energy impulses or variations. in the circuit thereof, serving as a cut-out switch 20 Further, said invention has for its object to for the electr c-mechanical device operated by provide a system of the character specified, in the system, and which the control tube thereof is operable to Fig. 4 is a view of one form of adjustable feedcause either abrupt changes in its plate or outback coupling which may be employed in the put current, or modulated variations thereof, accircuits of the control tube or valve. 25 cordi to the character of the energy impu ses Referring to the drawings, the electronic conor v r ti n pp to the System nd he w rk trol tube or valve In, of the usual type required 6 be d0 y Said Output Currentfor the purpose, includes plate ll, cathode I2 Further, said invention has for its object to h t d by filament l3, and grid l4. The outp o ide a Sy Of the Character specified, in put or plate circuit l5 isprovided with the ter- 30 which the control tube or valve thereof is ca minals 5 which the electrmmechanical 1 Fable of Operating P a triggffr action for vice, relay, instrument or other means H to be producing an abrupt r158 fall the output controlled or operatedis electrically connected. or work current for controlling the operation of plate circmt [5 includes the usual Source mechanical relays or other electro-mechanical of energy a capable of Supplying the current 35 devices requiring Substantial energy to operate and voltage required for operation of the system, the sameincluding the device ll. As an example, the

Further, said invention has for its ob ect to energy for Operation may be supplied from the prqvlde a system f the character spec1 fied m A. C. line through the step-down transformer which .means g included for tratslitmg 1-9, including the secondary IS in circuit with the ,0 f f i iffi usual full wave rectifying tube 20 m the output correspon. mg pa Vans ions or C circuit l5, having the usual circuit connections effective in the cncuits of the control tube or k for rectiiying the current supplied to the output valve foi contiolling the operation thereof. is h th t f Further, said invention has for its object to Guam 3 Q rang ormer I 45 provide a system of the character specified, in T .mput cncmt 21 f the tube F Includes a which the control Valve or tube is capable of coil or inductance 22 between the grid l4: and the self-oscillation under control of the impressed cathofie and e condense? 23'br1dged by capacity variations for varying the grid potential a res1tance gnd 24 dlsposed t e and hence the flow of working current or direct the gnd M and the C011 The Output cn'cult [5. of the tube ID has a coil or inductance 25 included therein disposed in inductive relation with the coil 22 to form a coupling capable of adjustment between the input and output circuits of thetube. In for causing the tube to oscil- 55,

current component in the plate or output circuit of the tube or valve.

Other objects will in part be obvious and in part be pointed out hereinafter.

To the attainment of the aforesaid, objects late under certain conditions, as hereinafter with each other and are grounded through the conductor 32. The two tubes [0 and 26 may be enclosed within one and the same envelope or bulb, if so desired.

The plate 21 of the tube 216 is connected to one end 33 of coupling coil 22, and the cathode 28 is connected to the opposite end 34 of said coil 22, the tube 26 as thus connected constitutingm as hereinafter more fully described, a variable capacity across the coil 22. The electronic tube 26 in the present invention constitutes means for causing a variation of capacity in the circuits of the tube 10- andtherefore does not operate as the usual amplifier or relay, and does not require in the output circuit 21-22-28 thereof a local source of energy, B-battery, or the like, for supplying energy required for amplification.

I have discovered that potential variations imposed on the grid 30 located between the plate 21 and heated cathode 23 cause, because of the electronic characteristics of the tube 26, a corresponding change in the electron flow or emis- 'sion resulting in a variation in capacity of said tube, which capacity variations are made to control the circuits of the tube In to throw the same into and out of oscillation.

The electrical energy or potential for exciting the grid 30' is supplied from-a suitable translating device, such as that shown in Fig-2, to the input circuit 36-of the tube 26 through the terminals 31'. -A-condenser 38 is inserted between the grid 30 and cathode 28 for by-passing any stray energy from the oscillating circuits around the translatingqmeans, and also for preventing capacity variations in the translating circuits connected'to-the terminals 31 from affecting the operation of the system. A condenser 39 also bridges the terminals IQ of the outputcircuit of the tube H) to provide a high frequency path bypassingthe device l!., A condenser 40 is also inserted in. the connection .41 by-passing the rectifier:20 toprovide a path for the high frequency currents around, therectifier to ground and to block the flow of direct or rectified current through the connection 4|. 4

Whenthe usual electronic device isemployed as the tube 25, it is preferable to impose normally a positive potential or bias on the grid 30 thereof to render the tube 26 critically sensitive or responsive to the energy impulses imposed thereon. The imposedpotential is preferably of an order preventing variation in capacity upon variation of the potential on the grid in one direction. S uch biasing means is illustrated in Fig. 1 as comprising a low voltage battery 42 in series with the grid 30 for; operating the tube 26 at a point on its characteristic curve which renders the tube critically sensitive in responding to the imposed energy impulses for causing the 'capacity variation.

In the system embodying my invention, the coupling capacity of thecontrol tube I0 is supplemented by an inductive coupling which may include distributed capacity for causing energy transfer between the input and output circuits of the tube for producing oscillation of any desired frequency, depending upon the period of the circuits. When the tube I0 is caused to oscillate, there will be a change in the direct current component in the output circuit l5 of the tube In. The magnitude of this change in plate current available for doing work, and the character thereof, depends primarily upon the characterof the potential variations imposed upon the grid I4 by the oscillations. For example, when the grid I4 is connected to the circuit through the small capacity 23 shunted by a relatively high resistance 24, say, of the order of three megohms, the grid will build up a negative potentialpharge thereon as the oscillation continues, causing the direct current component in the output circuit to be reduced to a low value, which is maintained so long as the system continues to oscillate. When the oscillations cease, the work current again rises to its maximum value for energizing the electro-mechanical device ll, the tube It under said conditions operating as a trigger or cut-out valve to cause an abrupt change in the flow of output or work current. By adjustment or change in the value of the resistance or leak 24, the rate at which the negative potential on the grid I4 is discharged may be varied to correspondingly vary or modulate the direct current component in the output circuit IS. The system, therefore, may be readily adapted for use as a repeater and amplifier of energy impulses having a definite period, such as occurs in telephony, radio, phonograph, pickup work, and in other arts.

In the present invention, the coupling provided by the coils 22 and '25 is critically adjusted so that a very slight variation of capacityin either grid or plate circuit will throw said circuits into and out of resonance to start and stop oscillation thereof, the coupling and the tube 26 as biased being coordinated so that the capacity variation is operative in one direction only from a normal value for controlling the oscillations. Preferably, the circuits are adjusted in capacity and inductance to oscillate at superaudible frequencies, particularly when the tube I0 is employed for modulating the output or work current in accordance with energy impulses having a definite frequency to be reproduced or repeated.

In Fig. 4 is illustrated simple means 43 for critically adjusting the coupling between the coils 22 and 25. This means comprises a tubular support 44 about which the coils 22 and 25 are wound one above the other in spaced relation.

The coupling or inductive relation between the coils 22 and 251s adjusted by means of the disklike metal core 45 carried by the adjustable handle or member 46 disposed within the tubular support 44. The member 46 has a threaded portion 41 of definite pitch operating in the base 48. Upon rotation of the member 46, the disk 45 is raised or lowered a definite amount per turn of the handle 4'. to vary the inductive effect of one coil relative to the other, depending upon the position of the disk 45. By proper design of the coil values and their spacial relation, the coupling may be accurately adjusted by movement of the disk 45 so that the circuits of the tube l 0 will be thrown into and out of oscillation upon the change in the capacity afforded by the tube 26.

The potential variations or impulses imposed upon the grid 30 for producing a capacity variation, may be obtained by translating various ature.

. sponse to a call for heat, the relay I? then operforms of energy, such as sound, light, heat, and other radiations, into their corresponding electrical equivalent for controlling the tube 26. In Fig. 2 is illustrated, as one example, a form of energy translating means 49 operating by a. variation in a resistance in response to excitation by energy impulses or variations, such as those of heat or light. In the diagram the energy responsive element comprises a resistance 50 exposed to the energy impulses, and capable of varying in resistance as a function of the temperature change thereof. The resistance 50 is disposed in a bridging circuit 5|, including the secondary 52 of a step-down power transformer 53 having its primary 54 in the circuit with the A. C. line for supplying the requisite energy to the bridge. The resistance 50 is opposed by resistance 55 capable of adjustment. The resistances or legs 50 and 55 are bridged at the corresponding ends 56 by the transformer secondary 52 which is sub-divided at its midpoint 51 to form. the other two legs of the bridge circuit and the same at the opposite ends 58 are bridged by the circuit connection 59. The midpoint 60 of the conductor 59 is connected by the lead Bl to one end of the primary 62 of the step-up transformer 63, and the midpoint 51 of the secondary coil 52 of the transformer 53 is connected by lead 64 with the opposite end of the transformer primary 52. The secondary 65 of the transformer 62 is connected to the input terminals 31 of the system above described.

Metals in general vary either directly or inversely in resistance with variations in temper- The element 58 varies in resistance directly with the temperature. The transformer 53 steps down the voltage to a low value of the order of 4 or 5 volts, so that no appreciable heating up of the resistance 56, due to current flow, will occur. If the variable resistance 55 constituting the opposing leg of the bridge circuit is made at a given temperature equal in value with that of resistance 55), there will be no flow of current to the transformer 63. However, if the resistance 55 is made either less than or greater than the value of resistance 58 at a given temperature, there will be a continuous flow of current through the transformer 53 which is proportional to the diiference in the values of the resistances of the legs 50 and 55. In the example illustrated, the resistance 50 is preferably made greater in value than the resistance 55. The difference in the resistances unbalances the bridge circuit to cause a flow of current through the transformer 63 which steps up the voltage by an appreciable amount for application to the grid 30. The two resistances are relatively adjusted so that the voltage or potential on the grid is sufficient to produce a capacity efiect causing oscillation of the tube 10 and to stop oscillation of said tube 58 upon a slight decrease in the temperature and hence of the resistance of the element 56. With this type of unbalanced bridge circuit the useof a separate bias on the grid 30, such as provided by the battery 42 (Fig. 1), is not needed. Utilizing a heat responsive element 50 having a greater resistance than that of element 55 renders the system particularly adapted for controlling the temperature conditions within buildings, because the normal resistance values at a given temperature and the characteristics of the transformers in the bridge circuit are such that a drop in the normal potential applied to the grid will throw the circuits of the tube It! out of oscillation and energize the relay I! in reating to supply the compensating heat to the building. Should the resistance 50, however, be

subjected to a temperature rise, although the potential applied to the grid 30 increases, the con- '7 trol tube It continues in oscillation to maintain the mechanical relay I! in its inoperative position, the increase in the potential on the grid 30 not affecting the oscillation of the tube It because of the characteristics of the coupling 2225 and? the bias on grid 30.

The translating system or bridge circuit 49 illustrated as one example of such device, is Very efficient in supplying the voltage variations to the grid 38 of the tube 28 for controlling the output or work current supply to the mechanical relay or other instrument ll. Utilizing the ordinary A. C. line for the electrical energy supply, the energy is supplied through a step-down transformer to the bridge circuit and to the grid 30 of the tube 26 through a step-up transformer, ample voltage therefore being available for application to the grid 39 While minimizing the currents flowing in the bridge circuit to reduce the heating effects thereof on the resistances 50 and 55. By utilizing a bridge circuit 49 in which the legs 50 and 55 are unbalanced, the bridge distinguishably responds to changes of temperature in both directions from a predetermined mean value of temperature to vary the positive potential on the grid 30. The tube 26 because of its rectifying action utilizes the positive voltage component of the alternating current.

In operation, assume that the coupling provided by the coils 22 and 25 is adjusted so that the circuits of the tube H) are thrown out of oscillation upon a variation in capacity accompanying a reduction of potential on the grid '30 of tube 26 from a normal value. If a bridge circuit of the character above described and shown in Fig. 2

is employed as the translating means, the constants thereof are chosen or fixed in accordance with the character of the incoming energy impulses and the operation to be effected thereby. The coupling 22-45 and circuit constants of the circuits of the tube H), by suitable adjustment in accordance with the principles of the invention, may be readily coordinated with the translating means including the tube 26 to be operatively responsive to the variations produced by the tube 26.

The tube 25 in the present invention constitutes a capacity in parallel with the coil 22 or coil 25, and capable of variation in accordance with the potential applied to the grid 30. I prefrably impose an initial positive bias on the grid Bil for rendering the tube 26 critically responsive to a small change in one direction of potential upon the grid 34] from a normal value for producing the required change in the capacity of the tube 25 to throw the circuits of tube It into and out of oscillation. The tube 28 has no source of potential in its plate circuit other than that due to the electron emitting effect of the heated cathode 23 of the tube, and therefore does not function in the present invention as a relay or amplifier. The capacity of the tube 26 between cathode and anode is varied, as herein described, by variation of potential on the grid element at of the tube. It is this variable capacity which when connected to the oscillating circuits of the tube H3 controls the oscillation thereof.

Assuming then that the circuits of tube m are in oscillation, a high negative potential obtained by the feed of energy from the plate circuit is maintained on the grid 14 through the condenser Y23 and the high resistance leak 24. This action reduces the flow of the direct current component in the output circuit to a minimum, causing the deenergization of the relay [1. Should the potential on the gridof the capacity controlling tube 2'6 decrease slightly for any reason, as, for example, because of a reduction in the temperature of the resistance of the bridge circuit 49, the resulting variation in the capacity of the tube 25 causes a change in coupling between the input and output circuits of tube l0, throwing said circuits out of oscillation, and allowing a maximum flow of the direct or work current through the relay ill to energize the same.

. By my invention I am able to control the flow of working current in the output of the tube IEI by a trigger action, so that the relay I! may be adequately energized and deenergized in response to the activating energy impulses. In some cases it is advisable to provide means for switching off entirely the flow of energy through the relay I1 and prevent partial energizing thereof by the residue of direct current component flowing when the tube 10 is oscillating. For this purpose I place a gas discharge device (Fig. 3), such as a neon tube, in series with the relay ll beyond the output terminals 16, and a resistance 66 in parallel with the relay I! and the gas discharge device 65 across the output terminals 16 of the system above described. The resistance 66 has a value compensating for and taking the place of the load I! when the latter is cut out of the circuit by operation of the tube 65. When the working potential across the terminals 16 surges to maximum upon the cessation of the oscillations in the output circuit, glow discharge across the electrodes of the tube 65 occurs, and the relay circuit closes to cause the actuation thereof. When the working potential drops below the value required to maintain the glow discharge, the relay circuit opens.

- to cause oscillation than it does to stop oscillation of the control tube it]. This characteristic of the system renders the same very stable in operation, particularly when utilized for room or building temperature control, and effectively prevents fluttering in the system, such as of the relay l'l. As an example of the operation, assuming that the resistance 59 of the bridge circuit has a value for maintaining a room temperature at 70 F. upon a small fractional drop in the temperature, the system will be thrown out of oscillation and the relay I! will respond to the demand for heat. As heat is supplied to the room, the resistance 50 will have to heat up to some fractional value above 70 F. before the potential rise on the grid 30 becomes suflicientto throw the tube In into oscillation and actuate the relay. The temperature of the resistance 50 may then drop to its normal value of 70 without affecting the oscillation. This potential lag in one direction of operation is an inherent characteristic of the system and depends upon the value of the circuit constants such as the inductances, grid r leak, etc. By adjustment of one or more of these constants the potential lag in one direction of control of the system may be Varied. By suitable selection of the resistance element 50, the latter may be coordinated with the system to control the limits oftemperature variation so that the system. will be stabilized at the desired normal temperature in both the oscillating and nonoscillating states. Further, the coupling 22-45 and biased tube 26 are coordinated so that a rise in temperature of the resistance element 50 from normal will not affect the oscillations.

My method and system for carrying out said method is particularly adapted for the detection and utilization of very weak energy impulses or variations, such as those of sound, light, heat, radio, electricity, and other radiations capable of being translated into potential variations or changes for exciting the system.

By suitable selection or adjustment of the circuit constants in accordance with the principles of the invention, the system becomes adapted for use in various fields or arts, such as heating, telephony, radio, television, and the like, and for operating and controlling various indicating and recording instruments or devices in response to various energy excitations. Further, the output or working current may be controlled according to the requirements of use, to produce an abrupt or trigger variation of the current in response to the energy impulses for operating various direct current devices, or to produce a Varying current modulated in accordance with the. incomingemergy impulses for operating various audio frequency devices, recorders, indicators, or the like.

No claim is made in this application for the translating means or bridge circuit per se, or to the same in combination with the electronictube circuit herein claimed, since the same constitutes the subject matter of a copending application, Serial No. 148,336, filed jointly by Maurice A. Michaels and myself on June 15, 1937. w

What I claim and desire to secure by Letters Patent of the United States is: Y

1. A system of the character. described, comprising an electronic tube having plate and grid circuits coupled together, an electronic tube-having the plate and cathode thereof connected in one of said circuits, said coupling and said lastnamed tube being coordinated to throw said circuits into and out of oscillation upon variation of said last-named tube, and means for imposing a biasing potential onthe grid of said last-named tube for preventing operation thereof upon variation of the grid potential thereon in. one direction from its biasing value.

2. A system of the character described, comprising an electronic tubehaving plate and grid circuits coupled together, an electronic tube having the plate and cathode thereof connected to said coupling in one of said circuits, said coupling and said last-named tube being coordinated to render said circuits responsive to variation of said last-named tube for throwing the circuits into and out of oscillation, a capacity between the grid and cathode of said last-named tube for preventing stray oscillations from affecting the grid thereof, and means for imposing a variable potential on the grid of said last-named tube for throwing said circuits into and out of oscillation,

said potential serving to normally bias said grid P for rendering said tube inoperative upon variation of the grid potential in one direction from its biasing value.

3. A system of the character described, comprising an electronic tube having plate, andgrid circuits coupled together, an electronic tube having the plate and cathode thereof connected to said coupling in one of said circuits, said coupling and said last-named tube being coordinated to render said circuits responsive to change thereof to and from substantially resonant relation for throwing the circuits into and out of oscillation, means for building up a potential on the grid of said first-named tube in response to the oscillations for varying the plate current in accordance therewith, means for imposing upon the grid of said last-named tube a biasing potential for preventing operation thereof upon change of grid potential in one direction from its biasing value, and a capacity between the grid and cathode of said last-named tube for preventing stray oscillations from afiecting the grid thereof.

4. A system of the character described, comprising an electronic tube having grid and plate circuits coupled together, an electronic tube having the plate and cathode thereof connected to said coupling to vary the capacity component thereof, said coupling and said last-named tube being coordinated to throw said circuits into and out of oscillation upon variation of said last-named tube, and means for imposing a variable potential on the grid of the last-named tube and serving to prevent operation of said tube upon variation of grid potential in one direction from its normal value.

5. A system of the character described, comprising oscillation generating means including an electronic tube having coupled grid and plate circuits, oscillation controlling means including an electronic tube having the plate and cathode connected to said coupling to cause variation thereof, and means responsive to energy excitation for imposing a variable potential on the grid of the second tube, said oscillation generating means and said controlling means being ordinated to render said oscillation generating means responsive to the variation of grid potential of the second tube in one line of direction relative to a given potential for throwing said first-named means into and out of oscillation and to prevent such response upon variation of the grid potential in the opposite line of direction, and a capacity connected between the grid and cathode of the second tube.

6. A system of the character described, comprising oscillation generating means including an electronic tube having coupled grid and plate circuits, said coupling being adjusted to render said circuits critically responsive to variation of coupling for throwing said circuits into and out of resonance to correspondingly control the oscillations therein, means for building up a potential on the grid of said tube, controlling means including an electronic tube having the plate and cathode thereof connected in said coupling to cause the variation thereof and means responsive to energy excitation for imposing a variable potential on the grid of the second tube, said oscillation generating means and said controlling means being coordinated so that variation of the 7 

